These models can squeeze through narrow gaps or gateways to work on sites that would previously have needed hand digging. And because they exert low ground pressure, they are useful for working on parts of a site where tree roots and turf are already in place.
Most mini excavators are also available with a selection of attachments.
The choice of machines can be bewildering. Dimensions, tracks, transport weight, hydraulics, operator comfort and visibility, serviceability and machine-matched attachments are just some of the aspects to consider when looking to buy or hire a mini excavator.
Selecting the right machine is critical. Unlike most other classes of machine, what appears to be the slightest increase or decrease in physical size can greatly affect a mini excavator’s sphere of application.
For landscape contractors, there are three key considerations surrounding mini excavators — transport, productivity and the constraints of the site.
In light of towing regulations, it is essential to work out how the machine will be transported to the site. The maximum gross weight that can be towed on a trailer with brakes is 3,500kg and there is a rule of thumb that suggests a vehicle should only be towing a trailer weighing less than 85 per cent of its kerb weight. This makes the 1.2 to 1.5 tonne mini excavator a popular choice.
When launching a new product into the 1.2 to 1.5 tonne sector, Bobcat reduced the weight of the 319 mini excavator to 1,271kg with a canopy and 1,400kg with a cab. This means the excavator and attachments, such as buckets and breakers, are easy to transport on a trailer.
The second consideration — productivity — relates to the digging depth and breakout force required. Clearly, the machine needs to give the productivity and performance you require, but the maximum digging depth, dump height and breakout force can vary widely.
It is also essential to consider how compact the machine needs to be. Think about site access. Several mini excavators, including the Bobcat 319, have expandable undercarriages that allow them to “breathe in” to negotiate narrow access points and then “breathe out” to provide the stability needed to dig and lift. This is also a useful feature if you need to straddle narrow trenches in cable-laying applications.
The size limitations of a site should also be added into the equation. The restrictions imposed by small sites, or those cluttered with obstacles and bounded by fences or walls, need not be a problem. A growing share of the market is accounted for by short-radius and zero-tail-swing (ZTS) excavators.
The design of ZTS units, such as the new Bobcat 430 and 435 excavators, eliminates the tail swing associated with conventional excavators, ensuring that the rear of the machine does not extend beyond the width of the undercarriage when slewing.
ZTS mini excavators can be positioned next to walls for digging, allowing the upper housing and digging arm to rotate through 180? to dump the bucket without the driver having to look back and worry about hitting anything with the back end of the housing.
It’s also well worth investigating the speed of travel across a site. The Bobcat 430 and 435 are both available in FastTrack versions that enable them to creep into position slowly but move swiftly — by excavator standards — between working positions.
These two machines also feature load-sensing hydraulic systems to provide smoother control and improved workgroup balance.
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